Say yes to the jizz.
Friend are friends and pals are pals, but buddies beat off together.
Not only is it cool to share the moment, there is no greater way to bond with your mate than to help him bate.
My favorite is not just being there while he spews, but taking a hands on approach of stroking him. Yes, my dude, bros helping bros is a thing. And, when he does you, try to do him the same way, catching the head in the same tempo and style of stroke length as he was doing you.
And, if I may, preventing a mess is simply good housekeeping. So, if while you are stroking him, he says, “oh, bro, I'm gonna cum,” you get your mouth on the head of that cock and start swallowing his baby batter. Mess avoided. But if you are in the house alone and have an opportunity for clean up afterward, there is almost nothing better that taking your man's love goo in your hand and using his sweet slime as lube for your own dick. Almost nothing better. What is better? Frotting, man. Laying on top of him, balls to shaved balls, stroking both cocks with one hand, like it was a cock with a nine inch girth. If he leaks a lot of precum, sweet. If not, whoever cums first helps the other by supplying a ton of warm lube. If you are sitting up, watch how high you each spew, I hit the ceiling a couple of times.
As far as cum swallowing. Taste your own first so you know what to expect when you get together. And, want to know a special treat? Eat pineapple the day before/day of, and oh my God, that is some great tasting stuff. You will actually lick his cock and balls afterward trying to get as much as you can.
I know it is just a two straight bros thing, but sometime, after you swallowed his cum, let him taste your mouth. A deep kiss from your bro is hot. Damn, it just made me hard again. I bet you do it twice in a row on that day.